At one point you may have denied Google access to the mic and the settings saved, never to ask again. When you click the microphone icon on the Google Chrome search bar at google.com, you see a link to Learn More, instead of being prompted to Allow or Deny permission (because you already denied it).

On Chrome for Mac you’ll see “Voice search has been turned off. Details”

Clicking on “Details” on Mac or “Learn More” on Windows 7 takes you to a page entitled “Voice search and voice actions on Chrome” where you can read about how great Voice Search is and how to enable Ok Google but there is no information about turning the mic on/allowing permission.

How do you adjust your permission settings for the microphone in Google Chrome?

You’ll see these options on Windows (similar on Mac):
Select “Ask me when a site requires access to my camera and microphone (recommended).” Click on Manage Exceptions. You may see some entries for Hostname pattern and Behavior. If you see the Hostname https://www.google.com:443 you will want the Audio to be set to “Allow.” If it says block, simply highlight this row and click the X to delete it. Then Google will ask for permission to access the mic when you return to google.com and click the microphone icon to use Voice Search. The problem should be solved now.

However, if it says “Allow” here and you are still having issues, just click on the URL to highlight it, then click the X to delete it. We’ll try and reset the process. If you see no entries for Hostnames here and are unable to type any in manually, that is also okay. Let’s make sure you don’t have any settings in Adobe that are at play:

After you’ve clicked Manage Exceptions, at the bottom, click the “Change” link in: “Adobe Flash Player camera and microphone exceptions are different. Change” and you will end up at Adobe Flash Player Global Privacy Settings:

Look for Google in the list of website settings. Delete it. Now you should have no settings regarding Google Chrome in your Chrome Settings or Adobe Flash Player: try to click the mic at google.com again. You should see Allow or Deny pop up.

You’ll find the basic instructions about setup and voice search examples on the Chrome voice search information page (but this page does not allow you to adjust the permission settings and the troubleshooting section doesn’t touch on Adobe). If you have problems after managing the Adobe settings though, the troubleshooting tips there could help.